Hi Bruce, I followed your arsenal marks thread to help identify the partial seki stamp, I purchased this locally from an acquaintance, he pointed out the arsenal mark and said it meant it was either non-traditional or possibly a tan stamp and could be traditional (I know he knew it was seki but suggested some ambiguity to help with the sale), as soon as I saw the blade I could see the hamon looked weak and not what I expected (and I didn't see grain of any kind, I've since identified the hamon as oil quenched), my gut feeling was it was non-traditional but was in complete type 98 fittings with tassel in fair/good condition so I knew as a military collectible it would be something I could later sell and it would give me some experience examining a non-traditional blade in wwii fittings (my mother was Japanese and was born in hawaii 4 months before pearl harbor, so the wwii connection has some personal interest even though I'm not a military collector). The blade has original patina and hasn't been disturbed but the condition is rough with edge nicking, evidence of bends, an edge twist and has scrapes and scratches suggesting it was whacked around or played with (I suppose it could have been in combat but it is what it is).
This was my first sword purchase so I looked at it as a positive learning experience (even though I wanted what I've since learned is Nihonto), I've been building a library and have been studying the details in various listings to learn the complex terminology and try to develop an understanding of what I find personally interesting in terms of form/smith/age etc (trying to avoid impulsive novice buys and understanding how a series of smaller purchases, while satisfying could have been put towards a single more important piece in a collection, that's the hard part of collecting anything, discipline!!). I think I want to focus on tanto/wakizashi perhaps collecting a few pieces but with a focus on study of the history and art form.
This is such a great forum and community, I was thrilled to have such a quick translation by Moriyama Koichi. And discovering the downloads section on this site is such an incredible resource (at some point a donation is going to be in order).